Wind turbine generator with hydraulic pump

ABSTRACT

Wind turbine generator with hydraulic pump Wind turbine, comprising a tower ( 2 ) and a head ( 6 ) mounted at an upper end of said tower ( 2 ), rotational around a head axis, wherein a propeller ( 9 ) is mounted to said head ( 6 ), rotatable around a propeller axis, wherein a hydraulic pump ( 10 ) is provided, driven by said propeller ( 9 ), wherein the hydraulic pump ( 10 ) is provided substantially in the propeller ( 9 ).

The invention relates to a wind turbine construction comprising at leasta hydraulic pump construction driven or at least drivable by windthrough at least one propeller.

Wind turbines using hydraulic pumps in stead of electrical generatorsmounted in the head or nacelle of the wind turbine are well known in theart.

U.S. Pat. No. 8,622,719 discloses a wind turbine generator in which aradial-piston pump is provided in the head or nacelle of the windturbine, connected to a hydraulic motor, which in turn is connected toan electrical generator. A propeller with a central hub is connected tothe head through a central axis which drives the hydraulic pump insidethe housing of the head. The pump is used for pumping oil.US2014/0086733 discloses a similar system.

From the prior art also wind turbines are known provided with othertypes of hydraulic pumps, such as centrifugal or radial pumps or axialpumps. In these known systems too the pump is provided either in thehead, driven by a shaft of the propeller extending into the housing ofthe head, or near a bottom or foot of the tower, driven by the shaft ofthe propeller through a system of shafts and gearings extending throughthe head and tower.

An aim of the present disclosure is to provide an alternativeconstruction for a wind turbine comprising a hydraulic pump. An aim ofthe present disclosure is to provide for a wind turbine having ahydraulic pump which is relatively easy to build and/or maintain,especially service. An aim of the present disclosure is to provide for awind turbine having a hydraulic pump, which allows for relatively easyservice of the hydraulic pump or parts thereof. An aim of the presentdisclosure is to provide for a system comprising a wind turbine having ahydraulic pump, which is low maintenance and requires short down timefor service. The disclosure further aims and provides methods andsystems for installing and/or maintenance of wind turbines and windfarms using hydraulic pumps.

At least one or some of these and other aims can be obtained with a windturbine, system and/or method according to the disclosure.

In a first aspect a wind turbine according to the disclosure comprises atower and a head mounted at an upper end of said tower, rotationalaround a head axis, wherein a propeller is mounted to said head,rotatable around a propeller axis. The propeller axis may be a physicalaxis or a virtual axis. A hydraulic pump is provided, driven by saidpropeller. According to the disclosure the hydraulic pump is providedsubstantially in or on the propeller.

In this disclosure a hydraulic pump should be understood as meaning atleast a pump for pumping fluids, such as water, for example fresh orsalt water, for example sea water, through a fluid circuit. Such pumpcan for example be connected to a further hydraulic pump or engine, orform part thereof. Such further pump or engine can for example be anengine or generator, for example for generating electrical currentand/or heat and/or cooling. A hydraulic pump of the present disclosurecan also be connected to other plants, such as industrial plants,accumulators for water or other pressurized fluid operator systems.

In this disclosure providing a pump substantially in or on a propellershould be understood as meaning that at least a substantial part of thepump is mounted to move with the propeller and rotating around the saidpropeller axis during use. A further part of the pump may be provided inthe head or nacelle of the wind turbine. The part mounted in or on thepropeller can preferably be placed on and be removed from the housing ornacelle with the propeller or at least with the hub of the propeller.

In embodiments the pump may comprise a series of cylinders mounted on orformed in a nave or axis extending from the head or nacelle. Thecylinders have a central axis extending outward from the nave or axis,preferably substantially racially and are open at a side facing outward.In each cylinder extends a piston having a head facing a bottom of therelevant cylinder and a foot portion facing outward, extending out ofthe relevant cylinder. A drive ring is mounted around the foot portionsof the pistons, which drive ring has a central opening which has anon-circular cross section, such that upon rotation of said drive ringaround the nave or axis, pistons are forced into, preferably into andout of the respective cylinders.

In embodiments at least a flexible lining ring or lining ring assemblyis mounted between said drive ring and the foot portions of the pistons,such that upon rotation of the drive ring the lining ring is flexeddriving the pistons into the respective cylinders.

In embodiments bearings are provided between said drive ring and thefoot portions of the pistons, such that upon rotation of the drive ringthe bearings force the pistons into the respective cylinders.

In preferred embodiments the cylinders are mounted having their openends on a circle extending symmetrically around the said nave or axis,such that the pistons can all move between first end positions furthestfrom the nave or axis and second end positions closest to the nave oraxis, the first end positions being at equal distances from the axis ornave and the second end positions being at equal distances from the naveor axis.

In embodiments the chive ring can have a central opening which has anundulating inner surface, such that upon rotation of the drive ringalternatingly a top and a valley of said surface will engage a footportion of a piston, directly or indirectly, for example through rollerbearings or a lining ring or ring assembly. In embodiments the drivering can have a central opening having a smooth, substantiallyelliptical surface for engaging the foot portions directly orindirectly, for example through roller bearings or a lining ring or ringassembly. In embodiments the drive ring can be provided with a centralopening defining a peripheral surface facing the pistons, rollers beingprovided in or on said surface for engaging the foot portions of saidpistons, directly or indirectly, for example through a flexible liner orliner assembly.

In embodiments each cylinder at a bottom end is provided with at least afluid inlet and a fluid outlet, coupled to a fluid inlet line and afluid outlet line respectively, which can extend through the nave oraxis into the housing. Preferably at least one of the inlet and theoutlet is provided with a one way valve, such that upon outward movementof the piston in the relevant cylinder fluid is entered through theinlet into the cylinder and upon inward movement of the piston saidfluid is forced out through the outlet.

In alternative embodiments the pump can be designed as an axial pump,wherein preferably a stator of said pump is connected to or formed bythe nave or axis, and the rotor is provided in or by a hub of thepropeller. In alternative embodiments the pump is provided with aplanetary traction or friction drive.

In embodiments a pump, for example for use in a wind turbine asdescribed, can comprise a non-circular drive for racially extendingpistons and/or cylinders, directly or indirectly engaging said pistonsand/or cylinders, whereas a traction and/or friction drive may beprovided, engaging said non-circular drive and a hub of a propeller, ora part engaging such hub, such as for example a further ring, forming agearing between the hub or at least the propeller and the drive ring.

In embodiments a wind turbine according to the disclosure can comprise acrane mounted on the head or provided by the head, with which thepropeller can be lifted. Preferably the propeller can be lifted with thecrane from the head to a position near a foot of the tower or viceversa. The crane is preferably provided on the head, especially on a topside of said head. In embodiments the crane can be designed for liftingthe propeller with a substantial part of the hydraulic pump, especiallythe part of the pump mounted in or on the propeller.

In embodiments the propeller with the part of the pump mounted in or onthe propeller can be replaced by a replacement propeller, such that themaintenance can be performed on the propeller removed without thenecessity of prolonged interruption of operation of the turbine.

In further elaboration, a wind turbine according to the disclosure,especially the hydraulic pump thereof, is connected to a generator. Thehydraulic pump may be connected to a generator through a hydraulic motoror hydro turbine, for example through a Pelton type hydro turbine.

In a further aspect the disclosure is directed to a system forinstallation and/or maintenance of a wind turbine, especially a windturbine according to the disclosure. The system comprises at least onevessel provided with a movable, preferably motion compensating platformsuitable for carrying a propeller system of a wind turbine. The platformis further suitable for transferring personnel to and from a windturbine to which the propeller system is to be mounted or from which thepropeller system is to be retrieved.

In a further aspect the disclosure is directed to a method forinstalling and/or maintenance of a wind turbine. In such method a towerwith a head can be placed in a selected position, and a propeller systemis shipped to said tower, the propeller system including at least asubstantial part of a hydraulic pump. The propeller system is lifted tothe head such that the hydraulic pump can assembled in the turbineand/or can be connected to a hydraulic circuit extending through thetower and the head. The propeller system is connected to the head.

In embodiments a method according to the disclosure can be designed formaintenance of a wind turbine farm, comprising a series of windturbines, preferably according to disclosure, wherein the series ofturbines comprises N turbines, each turbine comprising a propellersystem. At least one further propeller system is provided for exchangewith any one of the N propeller systems. For maintenance of a propellersystem the propeller system is removed from a wind turbine and replacedby said further propeller system, wherein the propeller system removedmay be shipped to a maintenance location remote from the relevant windturbine or farm or maintenance may be performed on location.

In the present disclosure wind turbines are disclosed both for off shoreor on shore installation. Preferably wind turbines according to thedisclosure are used off shore, wherein water, especially sea water isused as fluid pumped by the hydraulic pump.

In order to further elucidate the present invention, embodiments thereofshall be disclosed and discussed hereafter, with reference to thedrawings. Therein shows schematically:

FIG. 1 a number of wind turbines, connected to a plant;

FIG. 2 in cross section part of a turbine, showing a hydraulic pump;

FIG. 3 a hub of a propeller with a shaft or axis, and a hydraulic pumpmounted to the hub;

FIG. 4 a hydraulic motor according to the disclosure, in side view;

FIG. 5 a hydraulic motor according to FIG. 4, in front view;

FIG. 6 a hydraulic motor according to FIGS. 4 and 5, in partial crosssection along the line A-A in FIG. 4;

FIGS. 7A, B and C three positions of a pump according to the disclosure,especially according to FIG. 6, wherein a drive ring in FIG. 7B has beenrotated over 90 degrees relative to its position in FIG. 7A;

FIG. 8 an alternative embodiment of a hydraulic pump, in cross sectionalside view along line A-A in FIG. 4;

FIGS. 9A, B and C three positions of a pump according to the disclosure,especially according to FIG. 8, wherein a drive ring in FIG. 9B has beenrotated over 30 degrees relative to its position in FIG. 9A and in FIG.9C over 90 degrees relative to the position of FIG. 9A;

FIG. 10 a piston in a cylinder, connected to an inlet line and an outletline for fluid, with part of a drive system for the pistons, wherein twopositions are shown from the piston in the cylinder;

FIG. 11 a transmission between two drive elements in a hydraulic pump;

FIG. 12 schematically part of a hydraulic pump;

FIG. 13 a hydraulic pump with multiple rows of cylinders and pistons;

FIG. 14 in perspective view part of a wind turbine, with a crane;

FIG. 15 in side view part of a wind turbine according to FIG. 14;

FIG. 16 different steps in a method for mounting, dismounting and/orrepair of a propeller of a wind turbine and/or a hydraulic pump or partthereof;

FIG. 17 steps in propeller and/or pump repair and/or maintenanceincluding dismounting a propeller;

FIG. 18 steps in pump maintenance and/or repair from within a head of awind turbine;

FIG. 19 in cross sectional side view a wind turbine connected to agenerator;

FIG. 20 in perspective view a partially broken away head of a windturbine with a pump;

FIG. 21 in cross sectional side view part of a pump according to FIGS. 8and 9, in a single row embodiment; and

FIG. 22 in cross sectional side view part of a pump according to FIGS. 8and 9, in a double row embodiment, with part of a propeller shown.

In this description embodiments are shown and disclosed of theinvention, by way of example only. These should by no means beinterpreted or understood as limiting the scope of the present inventionin any way. In this description the same or similar elements areindicated by the same or similar reference signs. In this descriptionembodiments of the present invention shall be discussed with referenceto sea water as fluid to be pumped. However, other fluids could also beused in the present invention.

In this description references to above and below, top and bottom andthe like shall be considered, unless specifically stipulateddifferently, to a normal orientation of a wind turbine. This is forexample shown in the drawings, especially FIG. 1, wherein top, bottom,up and down are indicated by arrows and appropriate wording, forindicative purposes only. This does not necessarily reflect theorientation in which a turbine of the present disclosure or partsthereof have to be used.

In the drawings by way of example a wind turbine is shown having apropeller with two or three blades, extending in opposite directionsfrom a hub. It shall however be clear that any number of blades could beprovided in a propeller of the present disclosure, as is known in theart.

In the drawings by way of example a wind turbine is shown in which wateris drawn from a body of water, especially a lake or sea, and is pumpedup through the tower by the hydraulic pump, and clown again to agenerator. The fluid circuit including the hydraulic pump in the turbinemay be an open or closed circuit, and may comprise other fluids,especially in a closed circuit. Alternatively the hydraulic pump may beconnected to a generator in the head of the turbine. Alternatively thehydraulic pump may be used for pumping water, such as sea water, into astorage facility, such that said water can upon demand be used forpowering a generator connected to said storage facility.

FIG. 1 shows schematically a series of wind turbines 1, in thisembodiment shown as off shore installed wind turbines, i.e. windturbines 1 having a tower 2 placed on a foundation 3 positioned at thebottom 4 of open water 5, for example a sea or ocean. Each wind turbine1 has a head 6 mounted on a top end 7 of the tower 2, which head ornacelle 6 can rotate around a substantially vertical axis X of the tower2. At one end 8 of the head a propeller 9 is provided, mounted such thatit can rotate around a propeller axis Y extending substantiallyhorizontally, substantially perpendicular to the longitudinal axis X ofthe tower 2. Appropriate bearings and gearing are provided between thetower 2 and the head 6, as known in the art, for allowing controlledpositioning of the head relative to a prevailing wind direction.

In the wind turbine 1 a hydraulic pump 10 is provided, driven by thepropeller 9, as for example shown in FIG. 2. The hydraulic pump 10 isconnected to an inlet line 11 and an outlet line 12, as for exampleschematically shown in FIGS. 10 and 19, for fluid to be pumped. In theembodiment shown in FIG. 1 for example water can be pumped up from thebody of water 5, through the inlet line 11, and be pumped out throughthe outlet line extending down through the tower 2 and towards adestination for the fluid. In FIG. 1 by way of example such destinationis shown as a generator 13 provided in a plant 14, as will be discussed.Water is pumped from the tower 2 at relatively high pressure through apipeline 15 to the generator 13 for driving the generator 13 andgenerating electrical power.

In embodiments of the present invention the turbine 1 comprises a tower2 and a head 6 mounted at an upper end 7 of said tower 2, rotationalaround a head axis X, wherein a propeller 9 is mounted to said head 6,rotatable around a propeller axis Y, wherein the hydraulic pump 10 isprovided, driven by said propeller 9. The hydraulic pump 10 is providedsubstantially in the propeller 9. In embodiments the head 6 can comprisea nave 16, wherein the pump rotates with the propeller 9 at least partlyaround a part of said nave 16 extending from said head 6. The nave 16can form or can be provided with a substantially stationary part 17 ofthe hydraulic pump 10, and wherein the propeller 9 comprises arotational part 18 of the hydraulic pump 10. In such embodiments, as forexample shown in FIGS. 2 and 3, the nave 16 can comprise a first part 19inside said head 6 and a second part 20 which is releasably connected tosaid first part 19. Said second part 20 can then be provided in or bysaid hydraulic pump 10, extending into the propeller 9.

In embodiments the propeller 9 comprises a hub 21, as for example shownin FIGS. 2 and 3, from which the blades 22 of the propeller 9 extend. Ascan be seen in FIG. 3 a second part 20 of the nave 16 can extend fromthe hub 21, wherein the hub 21 can rotate around said second part 20.The pump 10 is connected to the hub 21, and to the second part 20, suchthat a rotation of the hub 21 relative to the second part 20 will leadto pumping by the hydraulic pump 10. The hub 21 can further be gearedand supported relative to the head 6 in a known manner, for example byappropriate bearings (not shown) between a surface 25 of the hub 21facing the head 6 and an adjacent surface of the head 6. As is shown inFIG. 3 the hub 21 can be formed such that for example the pump 10 isplaced directly beyond a main body 21A of the hub 21, for example on orover a nave 16, 16A, which should still be considered as at leastsubstantially in the propeller 9 or in the hub 21.

A fluid circuit 23 comprising the inlet line 11 and the outlet line 12extends through the tower 2 and the head 6, which fluid circuit 23comprises a part 24 extending inside a hub 21 of the propeller 9. Saidpart 24 comprises at least part of the hydraulic pump 10.

In embodiments of the present invention the hydraulic pump 10 isprovided in the hub 21 of the propeller 9, such that the pump 10 can beremoved from the head 6 together with the propeller 9. To this end forexample the inlet line 11 and the outlet line 12 have to be disconnectedfrom the circuit 23, and the connection between the first and secondpart of the nave 19, 20 has to be disconnected, after which thepropeller 9 can be removed with the hub 21 and pump 10, including thesecond part 20 of the nave 16. In this respect a nave 16 has to beunderstood as a construction or assembly of elements such as first andsecond parts 19, 20, which are stationary relative to the head 6 duringuse, and which support the pump 10 as well as part of the circuit 23.

Additionally or alternatively the pump 10 can comprise a mounting part26 which can be fixed removably in a stationary position relative to anave 16 in or extending from the head 6, or which can be connected tothe head 6, for mounting the pump. In such embodiment for removing thepump 10 the mounting part is released, as schematically shown in FIG.10. In embodiments as shown in FIG. 10 the pump 10 may have an innerpart 10A stationary fixed on a platform or carrier or such mounting part26, which can for example be bolted or otherwise be fixed to the head 6in a stationary position. The hub 21 with a moving assembly 10B of thepump 10 is supported by the said mounting part 26, such that it canrotate around the propeller axis Y, around said stationary part 10A. Insuch embodiment releasing the mounting part 26 from the head 6 anddisconnecting the circuitry 23 from the pump 10 will allow removal ofthe propeller 9 with the pump 10 from the head 6.

At least one valve 27 may be provided in the circuitry 23 for closingthe circuitry 23 when removing the pump 10.

By allowing the pump 10 to be placed in and/or removed from the turbine1, especially to and/or from the head 6, with the propeller 9 or atleast with the hub 21 makes it very easily possible to assemble and,especially, provide maintenance to the turbine 1, without a prolongedperiod of non operation or down time, and hence improve efficiency ofthe turbine. Moreover it makes for a very practical and inexpensivesystem and method for construction, maintenance and/or repair.

As is for example schematically shown in FIG. 2 in cross section, thehydraulic pump 10 can comprise a series of pistons 30 movable incylinders 31. The cylinders 31 can for example be mounted stationaryrelative to the nave 16 and/or mounting part 26, the pistons 30 beingpushed into and allowed to move out of said cylinders 31 by a rotationof the propeller 9, especially the hub 21 around said axis Y. Inlet 11and outlet 12 can be connected to the cylinders 31, as for exampleschematically shown in FIG. 10, such that when a piston 30 is pushedinto the cylinder 31 by an operating or drive mechanism 32, as will bediscussed, in the direction F_(in) as indicated, towards a bottom end 33of the cylinder 31, fluid such as water is forced out of the cylinder 31through the outlet 12, whereas when the piston 30 moves in oppositedirection F_(out), liquid is drawn into the cylinder through the inlet11. Appropriate one way valves 11A, 12A may be provided in the inlet 11and outlet 12 respectively. A single row of cylinders 31 and pistons 30can be provided, or multiple rows, as can be seen in for example FIGS. 2and 11. By providing multiple rows relatively small cylinders can beused, nevertheless providing for a relatively large volume of liquid tobe pumped.

In embodiments an end 34 of each piston 30 can be connected to the drivemechanism 32, such that the piston 30 can be pushed in the directionF_(in) as well as pulled in the direction F_(out). Additionally oralternatively the fluid can be pressurized in the inlet line 11slightly, such that it is forced into the cylinder through an inlet 11pushing the piston 30 in the direction F_(out).

FIG. 4-6 disclose schematically an embodiment of a pump 10 with anembodiment of a drive mechanism 32, by way of example. The pumpcomprises an inner part 10A and an outer part 10B, the outer part 10Bbeing rotatable around the inner part 10A around a pump axis P, which inuse preferably coincides with the propeller axis Y. The outer part 10A,shown circular, is provided with mounting provisions 35 for connectingit to the hub 21 of the propeller 9. Here the provisions 35 are shown asholes extending through a flange 36 for bolting the outer part 10B ofthe pump to the hub 21. The inner part 10A is also provided withmounting provisions 37, for mounting the inner part to the nave 16and/or the mounting part 26 or otherwise in a position fixed relative tothe housing, such that it will not rotate around the propeller axis Ywhen the propeller rotates around said axis Y. To this end in theembodiment shown the inner part comprises a series of holes 37 extendingthrough a central part 38, substantially parallel to the pump axis P,through which the said central part 38 can be bolted into position.

In the central part 38 a series of cylinders 31 is provided, each havinga central axis A_(c) extending substantially radially outward from theaxis P, from a bottom end 33 to an opposite open end 39 facing outward.The inlet and outlet 11, 12 extend through the central part 38, forexample through a nave 16 into the head 6 and down the tower 2. Inembodiments the cylinders 31 can be integral to the central part 38. Inother embodiments the cylinders can be mounted into said central part38, for example such that they can be retracted from the central part 38into a central opening 40 or the nave 16, for example for maintenancefrom within the head 6.

The central part 38 can have a substantially circular outer periphery 41in which the open ends 39 of the cylinders lie and/or open. Pistons 30are fitted inside the cylinders, having an end 34 reaching out of thecylinder 31 and a head 42 facing the bottom end 33 of the cylinder. Aflexible lining ring or ring assembly 43 is provided extending over theends or foot portions 34 of the pistons. The lining ring 43 can forexample be a metal or plastic ring or a ring made of a compound orsandwich of layers of metal and plastic. The ring may in a relaxedposition have a substantially circular cross section with a diameterD_(liner) which is slightly bigger than the outer diameter D_(central)of the central part 38, measured on the periphery 41, such that when thesaid liner ring 43 is placed around the central part 38 there will be aspace between the periphery 41 of the central part 38 and the inner sideof the ring 43.

A drive ring 44 is provided, having a non circular and preferablysubstantially elliptical central opening 45, extending around thecentral part and liner ring 43, such that the liner ring 43 is forcedinto a similar non-circular and preferably substantially ellipticalshape, as for example shown in FIG. 6. Bearings 46, such as for examplerollers may be provided between an outer surface 47 of the liner ring 43and an inner surface 48 of the central opening of the drive ring 44. Theconfiguration of the drive ring 44, liner ring 43 and bearings 46 ispreferably such that the short axis or smallest width W₄₃(min) of theliner ring 43 is about the same as the outer diameter D_(central) of thecentral part 38, whereas the longer axis or largest width W₄₃(max) islarger than the outer diameter D_(central) of the central portion 38. InFIG. 6 the long axis W₄₃(max) is shown vertically, the short axisW₄₃(max) horizontally. Hence in this embodiment above and below thecentral portion 38 spaces 49 are provided to allow the pistons 30 inthese areas to move outward, to a first end position furthest from thenave or axis P, from a second end position closest to the nave or axisP, whereas at the left and right side of the central portions the linerring 43 is close to or even in abutment with the periphery of thecentral portion 38 and hence the relevant pistons 30 have been forcedinto a second end position, closest to the nave or axis P.

Rotation of the drive ring 44 around the flexible liner 43, whichpreferably is relatively resilient, will flex the liner ring 43 suchthat the long axis W₄₃(max) and short axis W₄₃(min) will rotate aroundthe axis P, as is schematically shown in FIGS. 7A and B. In FIG. 7A thelong axis W₄₃(max) extends substantially vertically, the short axisW₄₃(min) substantially horizontally, whereas in FIG. 7B, in which thechive ring 54 has been rotated over an angle of about N*90 degreesaround the axis P of the pump, N being an integer, and relative to thecentral part 38 which is held stationary. The liner ring 43 preferablyis stationary too, that it does only flex but not rotate around the axisP. Hence upon rotation of the chive ring 44 the lining ring 43 isflexed, driving the pistons 30 into the respective cylinders 31. Thebearings or rollers 48 will reduce friction between the drive ring 44and the liner ring 43.

The drive ring 44 may be directly connected to or from an integral partof the outer part 10B of the pump 10 and hence will rotate with the hub21 and propeller 9 at the same rotational speed. In embodiments theliner ring or ring assembly 43 and/or rollers 46 may be omitted, suchthat for example the inner surface 48 of the drive ring 44 directlyengage the pistons 30 or the rollers engage the pistons 30. The pistonspreferably have a slightly outward bulging spherical outer end in orderto smooth the contact between the piston 30 and the drive mechanism 32.

In embodiments the drive ring 44 may form an non-circular drive for thepistons and/or cylinders, directly or indirectly engaging the pistons30, whereas a traction and/or friction drive may be provided, engagingthe drive ring 44 and the hub 21 or a part engaging the hub 21, such asfor example a further ring 51, forming a gearing 70 between the hub 21or at least the propeller 9 and the drive ring 44. Such gearing 70 canhave an advantage in that it may increase rotational speed of the drivering 44 relative to the hub 21 and/or propeller 9. Moreover,additionally or alternatively such gearing may lower torque on or fromthe propeller 9. Such gearing 70 may have the advantage that arelatively slowly rotating propeller 9 may provide for a relatively fastmoving drive ring 44 and hence fast moving pistons 30, increasing volumeof liquid to be pumped and/or pressure of liquid pumped.

In the embodiments shown gearing 70 may be provided by the drive ring 44having an outer, circular peripheral surface 50, whereas the outer part10B comprises an outer ring 51 with a central opening 52 provided withan inner peripheral surface 53. Between the said peripheral surfaces 50,53 a series of bearings or rollers 54 is provided, such that uponrotation of the propeller 9 and hub 21 the bearings or rollers 54 arerotated, forming a gearing between the outer ring 51 and the drive ring44. The gearing may be defined inter alia by the diameters of outersurface of the drive ring 44 and the inner surface of the outer ring andthe diameter of the bearings or rollers 54. In embodiments the bearingsor rollers can have a constant diameter. As schematically shown in FIG.11 the bearings or rollers 54 can have a first part 54A having adiameter D54A and a second part 54B having a diameter D54B, which issmaller that the diameter D54A, thus providing for a stepped surface 55.The inner surface 53 of the outer ring 51 may for example engage thesecond part 54B, the outer surface 50 engaging the first part 54A. Hencea drive ration is defined between rotation of the outer ring 51, whichmay rotate with the propeller 9, and the drive ring 44, driving thepistons 30.

In preferred embodiments the cylinders 30 are mounted having their openends on a circle extending symmetrically around the said nave or axis P,such that the pistons 30 can all move between first end positionsfurthest from the nave or axis and second end positions closest to thenave or axis, the first end positions being at equal distances from theaxis or nave and the second end positions being at equal distances fromthe nave or axis.

In embodiments the drive ring 44 can have a central opening 45 which hasan undulating inner surface 48, for example as shown in FIGS. 12 and 13,such that upon rotation of the drive ring 44 alternatingly a top 48A anda valley 48B of said surface 48 will engage a foot portion of a piston30. Such engaging can be directly or indirectly, for example through alining ring or ring assembly 43. In FIG. 12 the central portion 38 isshown having grooves or splices 57 extending in the axial direction ofaxis P, for mounting the central portion on a nave 16 with correspondingribs (not shown), such that rotation of the central portion isprevented.

FIGS. 8 and 9A-C show an embodiment of a pump 10 according to thedisclosure, which is similar to that of FIG. 4-7. The same parts orelements have the same reference signs. In this embodiment however eachpiston 30 is provided, at the outward facing end or foot portion 34 atleast one bearing 60 is provided, engaging the inner surface 48 of thedrive ring 44. Rotation of the drive ring 44 hence again forces thepistons 30 into the cylinders 31 or allows them to be pushed outwardagain.

In the embodiment shown each piston 30 is provided with a bearingassembly 61, comprising at least two bearings 60, such as side by sideroller bearings 60 having parallel roll axis 62, carried in a bearingholder or boogie 63. The bearing holder 63 can be mounted on the footportion 34 of the piston 30 trough a pivot axis 64, for exampleextending substantially parallel to the roll axis 62 of the bearings 60.This allows the position of the bearing holder 63 relative to the piston30 to shift corresponding to the relevant portion of the surface 48 ofthe drive ring 44 engaging the bearings 60.

In the embodiments of FIG. 4-7 and of FIGS. 8 and 9 five cylinder-pistonassemblies are shown, by way of example only. It shall be clear that anynumber of cylinder-piston assemblies can be provided, depending i.a. onthe size of the cylinders and pistons 30, 31 and the available space forthe pump, for example depending on an inner volume and diameter of a hub21, head 6, size of a nave or mounting part, propeller size and thelike.

In FIG. 12 it is shown that multiple parallel rows of cylinders andpistons 30, 31 can be provided. The drive mechanism 32 can be designedto drive pistons in a column parallel to the axis P simultaneously andin sync, such that they reach their end positions at the same time.However they may also be driven to reach their end positionsalternatingly, such that at a given moment in time one of such pistonsis moving in an outward direction when another of said pistons in suchrow is moving in the opposite inward direction Pin, thus at least partlycompensating forces.

As is shown in FIG. 1 a wind turbine 1, especially a pump 10 of thedisclosure can be connected to a generator 13 provided in a plant 14.Water is pumped from the tower 2 at relatively high pressure through apipeline 15 to the generator 13 for driving the generator 13 andgenerating electrical power. In the embodiment shown the generator 13 isconnected to the pipeline through a pump 60, especially through a Peltontype pump. The generator 13 may be a multiple drive generator 13,wherein a first drive is provided by said pump 60 and a second drive isprovided by a further type drive 61. Such second type drive 61 may forexample be an incinerator type drive, such as for example a fossil fueldrive or an earth heat driven drive, tidal drive, solar powered drive orwaste heat driven drive or the like.

Instead of connecting the pipe line 15 directly to a generator 13, waterpumped by the pump 15 can be stored in a storage system, for example awater tank or basin, or such reservoir, for driving a generator such asa turbine by again releasing the water from such reservoir.Alternatively the water pumped can be used for other purposes.

In embodiments a wind turbine, for example as discussed here before, canbe provided with a crane 100 for lifting the propeller 9 or at least thehub 21 and/or the pump, preferably the hub 21 with the pump 10 or partsthereof. In the embodiment shown the crane 100 can be mounted on thehead 6, especially on a top side 101 thereof. A crane 100 can forexample have a foldable and/or telescoping arm 102, such that a free end103 thereof can be moved between a first position, shown in FIG. 14,moved away from above the hub 21 of the propeller 9 and a secondposition, shown in FIG. 15, in which said free end 103 is positionedabove the hub 21. A hoisting line 104, for example a cable or chain, canbe connected to the hub 21 of the propeller 9, such that the crane 100can bear the weight of the propeller 9, after which the propeller can bereleased from the head 6 and can be lowered, for example to the groundor water level or a vessel or the like, for transport, inspection,maintenance, repair or other handling of the propeller or parts thereof,for example a pump 10 or part thereof, if provided for. Similarly thepropeller 9 can be lifted upward to the head using the crane 100. In theembodiment shown the crane 100 is pivotable relative to the head 6, suchthat it can be stored in a retracted and/or folded in position, forexample a position against an outer surface of the head or in a storagebay or other such provision 105.

By providing a crane 100 the need for heavy equipment to be brought toand from the wind turbine, such as floating docks, cranes and the likeis prevented.

For hoisting parts of a wind turbine with the crane 100 also otherprovisional can be connected to the line 104, such as but not limited toa hoisting basket, magnet or the like, for holding and/or containingsaid parts.

FIG. 16 schematically shows different steps of dismounting and mountinga propeller 9 or at least a hub 21 of a propeller 9 of a wind turbine 1.This may or may not include part of or an entire hydraulic pump 10 asdiscussed.

In this embodiment the hub 21 is connected to the head 6 by a mountingpart 26. The mounting part 26 can for example be angular, such that afirst part 26A extends below the head 6 and a second part 26B extends infront of the head 6. Appropriate bearings are provided (not shown) formounting the hub 21 and hence the propeller 9 to the mounting part 26,especially to the second part 26B such that the propeller in use canrotate around the propeller axis Y. The mounting part 26 can beconnected for example by bolting it to the head, bolts indicated byreference signs 26C, preferably accessible from inside the head 6.

When the propeller 9 has to be removed, the hoisting line 104 can beconnected to the hub 21 and/or the mounting part 26 in an appropriatemanner, where after the mounting part 26 can be released from the head6. Then the hub 21 with the mounting part and if appropriate the blades22 can be lowered along the tower 2 onto for example a platform 105 atthe foot of the tower 2. In off shore applications the platform 105 mayfor example be a motion compensating platform as known from Ampelmann,The Netherlands on a vessel 106. Then the hub 21 and/or mounting part 26can be released from the hoisting line 104 and be brought to a differentlocation, can be serviced, inspected or otherwise handled, for examplecleaned. After the appropriate handling the hub with the mounting part26 can again be hoisted up to the head, to be refitted. Alternativelythe hub 21 and/or the mounting part 26 can be exchanged for another hub21 and/or mounting part 26, the original part(s) being serviced ordiscarded.

In embodiments a series of wind turbines 1 can be provided, for examplein a wind farm, for example N wind turbines, whereas at least one sparepropeller 9 and/or hub 21 and/or pump 10 is provided, i.e. there are atleast N+1 propellers, hubs and/or pumps available for said wind farm.This means that at any time a propeller, hub and/or pump can be removedfrom a wind turbine 1 and replaced by the spare one, which can then beserviced, for example on site. The down time for the wind turbines insuch wind farm can thus be limited considerably.

FIG. 17 shows a story board for an embodiment of a method of thedisclosure, in sixteen images. This is only discussed by way of exampleand should by no means be understood as limiting the scope of thepresent disclosure. In this embodiment an off shore wind farm 110 isserviced, using a vessel 106 with a motion compensation platform 105,such as an Ampelmann system.

After briefing personnel and on-shore preparations (step 1) the vessel106 will take personnel and equipment to the windfarm (step 2) andpersonnel will change into appropriate gear, such as personnelprotection equipment (PPE) (step 3). Personnel 107 is dropped off at awind turbine 1 according to the disclosure (step 4), preferably usingthe platform 105. In the wind turbine preferably a control system 108 isprovided with which a maintenance mode can be switch on (step 5) bywhich at least the propeller 9 is brought into a safe position formaintenance. Then personnel 107 goes up to the head 6 by an elevator orstairs, preferably inside the tower 2 to access the head or nacelle(step 6) and allowing personnel access to the crane 100. The crane 100can be activated, such that it is brought into an extended position forattaching the hoisting line 104 to the propeller 9, especially the hub21 and/or a mounting part 26 (step 7). Then the propeller 9 and themounting part 26, also referred to as DOT system 111, can be releasedfrom the head 6 (step 8) such that it can be lowered to the platform 105using the crane 100 (step 9). A spare DOT system 111 can be placed onthe platform 105 or at least be hoisted up to the head using the crane100 (step 10) to be attached to the head 6 (step 11). Then the hoistingline 104 can be released from the DOT system 111 and the crane 100 bebrought back in the storage position, after which the personnel 107 cango back down through the tower 2 (step 12) and the maintenance mode canbe deactivated (step 13) such that the wind turbine can be operativeagain. The personnel can be picked up by the vessel 106, preferablyusing the platform 105 again (step 14). The DOT system 111 removed canfor example be serviced on board of the vessel 106 (step 15) whereas thevessel 106 can sail to the next wind turbine 1 in the wind farm, usingthe DOT system 111 on board as a spare for said next wind turbine,starting a next cycle at step 4 as discussed before, preferablyrepeating the process until all wind turbines in the wind farm have beenserviced.

FIG. 18 schematically shows a story board for maintenance performed on awind turbine 1, especially a pump 10 thereof, which may be done fromwithin the head 6 or for example on a vessel 106 in step 15 as discussedwith reference to FIG. 17. FIG. 18 schematically shows ten steps in suchmaintenance. First appropriate tools and spare parts, for examplegaskets are collected (step 15.1) after which personnel will access thepump 10, for example through the central opening in the central part 38of a pump 10 as discussed previously (step 15.2). To this end the DOTsystem 111 may for example be placed substantially horizontally, a nose21A of the hub 21 facing upward. Then a manifold 112, comprising forexample inlet 11 and outlet 12 connections, may be released (step 15.3)after which it may be removed (step 15.4). Then the relevant cylinder 31may be removed and/or the relevant piston 30 may be taken out of thecylinder 31 (step 15.4) for example for inspection of and, if necessary,replacement of the gaskets 30A (step 15.5), after which the piston 30and/or cylinder 31 can be re-installed (step 15.6). Then the manifold112 can be replaced (step 15.7) and be bolted back in position (step15.8) and properly connected. The steps 15.3-15.8 can be repeated forall cylinders 31 of the pump 10. Then, after gathering the tools (step15.9) the personnel can leave the DOT system 111 again (step 15.10) andthe pump 10 is ready for installment in the same or another windturbine.

FIG. 19 shows an alternative use of a wind turbine 1 of the disclosure,in which the pump 10 is integrated in a closed circuit for a firstfluid, for example oil. The pump 10 is provided, as discussed, at leastpartly and preferably substantially entirely in the hub 21 of thepropeller 9. A motor 113 is provided in or near the tower 2, for exampleat a foot 114 of the tower 2. A first, low pressure line 115 extendsfrom the motor 113 up to the pump 10, especially the inlets 111 thereof,whereas a second, high pressure line 116 extends from the pump 10,especially the outlets 12 thereof, down to the motor 113. The firstfluid is hence pumped up to the pump 10, where the pressure is increasedby the pump 10 driven by the propeller 9. Then the high pressure fluidforced down drives the motor 113. The motor 113 chives a second pump117, for example a salt water pump, which can pump water, for examplecollected from the body of water 5 in which the wind turbine is placed,to a generator 13, for example on a platform central to a wind farm. Thegenerator 13 can be driven by the sea water pressurised by the secondpump 117. In such embodiment the pump 10 need not be salt watercompatible.

FIG. 20 shows schematically, in perspective view, part of a wind turbine1, with a partly broken away head 6, showing a pump 10 with partlybroken away housing, and a combined inlet line 11 and outlet line 12.

FIGS. 21 and 22 show in cross sectional side view part of a pump 10,partly broken away. As can be seen in FIG. 21, 22 and e.g. FIG. 4 thepump 10 can be substantially mirror symmetrical over a plane A-A asshown in FIG. 4, extending perpendicular to the rotation axis P of thepump and/or the propeller axis Y.

In FIG. 21 a single row embodiment is shown, that is an embodiment of apump 10 with a single row of cylinders 31 with pistons 30. Each pistoncomprises a boogie 63 with bearings 60 carried on a piston foot 34,running against an inner surface 48 of the drive ring 44. In FIG. 22 anembodiment is shown in which two parallel rows of cylinders 31 withpistons 30 is provided. As can be seen in FIG. 22 especially the outerring or rings 50 can be connected to the propeller 9, partly shown tothe right in FIG. 22, through a hub 21. Thus upon rotation of thepropeller 9 the hub 21 will rotate around the propeller axis Y, rotatingthe ring or rings 50 and hence the drive ring 44, through gearing 70.This in turn drives the pistons for pumping.

As can be seen in FIG. 22 each row R of cylinders 31 and pistons 30 canbe formed by basically a pump 10 as shown in FIG. 21, such that a pump10 can be modular, wherein each module M can for example comprise onerow R, outer rings 50 being connected to each other directly and/orthrough the hub 21. Hence scaling is easily possible. In embodiments aclutch can be provided between all or some of the modules M, allowingsome or all of the modules M in a pump 10 to be used, depending on forexample wind available for driving the propeller.

The invention is by no means limited to the embodiments specificallydisclosed and discussed here above. Many variations thereof arepossible, including but not limited to combinations of parts ofembodiments shown and described. For example the cylinders and pistons31, 30 can be provided in the chive ring, facing radially inward,wherein the central portion is used to drive the pistons in a radialdirection, relative to the pump axis. In such embodiment it may bepreferable to connect the central portion 38 to the hub 21 of thepropeller 9 and mount the drive ring stationary on a mounting part 26.Also combinations are possible of cylinders in the drive ring andcylinders in the central portion. A mounting part may be a separate partor may be a part of the head 6. As discussed different types of pumps 10can be used, such as but not limited to centrifugal pumps, a pump usinga planetary traction or friction drive or an axial pump as known in theart. Such pump is mounted in the propeller 9, especially in a hub 21thereof, such that the pump can be removed from the head 6 together withthe propeller 9. In embodiments a crane can be provided in a differentposition, for example in the head 6 or on the tower 2.

These and many other amendments are considered to have been disclosedherein also, including but not limited to all combinations of elementsof the invention as disclosed, within the scope of the invention aspresented.

1. A wind turbine, comprising a tower and a head mounted at an upper endof said tower, the head being rotational around a head axis, wherein apropeller is mounted to said head, the propeller being rotatable arounda propeller axis, wherein a hydraulic pump is provided and configured tobe driven by said propeller, wherein the hydraulic pump is providedsubstantially in the propeller.
 2. The wind turbine according to claim1, wherein the head is provided with a nave, wherein a movable part ofthe hydraulic pump rotates with the propeller at least partly around apart of said nave, wherein said nave forms or is provided with asubstantially stationary part of the hydraulic pump, and wherein thepropeller comprises a rotational part of the hydraulic pump.
 3. The windturbine according to claim 2, wherein said nave comprises a first partinside said head and a second part which is releasably connected to saidfirst part, wherein said second part is provided in or by said hydraulicpump.
 4. The wind turbine according to claim 1, wherein a fluid circuitextends through the tower and the head, which fluid circuit comprises apart extending inside a hub of the propeller, which part comprises atleast part of the hydraulic pump.
 5. The wind turbine according to claim4, wherein the fluid circuit comprises at least one valve provided in ornear the head for disconnecting a fluid inlet channel of said circuitfrom the hydraulic pump, and further provided with at least a secondvalve in or near the head for disconnecting an outlet channel of saidcircuit from the hydraulic pump.
 6. The wind turbine according to claim1, wherein the pump is a multi: piston pump, comprising a central partand a drive ring extending around the central part, wherein: the centralpart comprises a series of radially outward facing cylinders withpistons movable in said cylinders in said radial direction, relative toa central axis, wherein the drive ring engages the pistons directly orindirectly for at least forcing the pistons radially inward; and/or thedrive ring comprises a series of radially inward facing cylinders withpistons movable in said cylinders in said radial direction, relative toa central axis, wherein the central portion engages the pistons directlyor indirectly for at least forcing pistons radially outward.
 7. The windturbine according to claim 6, wherein the drive ring comprises an inwardfacing, non-circular surface, engaging the pistons directly orindirectly.
 8. The turbine according to claim 7, wherein, between theinward facing, non-circular surface of the drive ring and the pistons, aflexible ring or ring assembly is provided that is configured to flexupon rotation of the drive ring, for driving the pistons.
 9. The windturbine according to claim 7, wherein between the inward facing,non-circular surface of the drive ring and each piston at least onebearing is provided, carried by a bearing carrier or boogie, for drivingthe pistons upon rotation of the drive ring.
 10. The wind turbineaccording to claim 1, wherein the hydraulic pump is mounted to the headusing a mounting provision also supporting the propeller, wherein thepropeller comprises a hub with one or more blades connected thereto,wherein the hub is mounted on at least one bracket which extends fromthe hub, which bracket is releasably connected to the head.
 11. The windturbine according to claim 1, wherein the propeller comprises a hub withone or more blades connected thereto, wherein the hub is mounted by atleast one gear and/or a bearing, such that the hub can rotate relativeto the head by said at least one gear and/or said bearing.
 12. The windturbine according to claim 1, wherein the hydraulic pump comprises anon-circular drive for radially extending pistons and/or cylinders,directly or indirectly engaging said pistons and/or cylinders, andwherein a traction drive and/or a friction drive is provided, engagingsaid non-circular drive and a hub of the propeller, or a part engagingsuch hub, forming a gearing between the hub or at least the propellerand the non-circular drive.
 13. The wind turbine according to claim 1,wherein a crane is mounted to the head or provided by the head, withwhich the propeller can be lifted from the head to a position near afoot of the tower or vice versa, wherein the crane is provided on a topside of said head.
 14. The wind turbine according to claim 13, whereinthe crane is provided for lifting the propeller with at least part ofthe hydraulic pump.
 15. The wind turbine according to claim 1, whereinthe propeller with the hydraulic pump or at least a part thereofprovided in or by the propeller is exchangeable for a replacementpropeller with hydraulic pump or the relevant part thereof.
 16. The windturbine according to claim 1, wherein the hydraulic pump or the partthereof provided by or inside the propeller is accessible from withinthe head.
 17. The wind turbine according to claim 1, wherein thehydraulic pump is connected to a generator through a hydraulic motor.18. The wind turbine generator according to claim 17, wherein thegenerator is a multiple drive generator, wherein a first drive isprovided by said pump and a second drive is provided by one of the groupconsisting of: an incinerator type drive, a fossil fuel drive, an earthheat driven drive, a tidal drive, a solar powered drive, and a wasteheat driven drive.
 19. (canceled)
 20. (canceled)
 21. A system forinstallation and/or maintenance of the wind turbine according to claim1, wherein the system comprises at least one vessel provided with amovable, motion compensating platform suitable for carrying a propellersystem of the wind turbine, wherein the platform is further suitable fortransferring personnel to and from a wind mill to which the propellersystem is to be mounted or from which the propeller system is to beretrieved.
 22. A method for installing and/or maintenance of a windturbine, wherein a tower with a head is placed in a selected position,and a propeller system is shipped to said tower, the propeller systemincluding at least a substantial part of a hydraulic pump, wherein thepropeller system is lifted to the head such that the hydraulic pump canbe assembled in the wind turbine and/or can be connected to a hydrauliccircuit extending through the tower and the head, wherein the propellersystem is connected to the head.
 23. The method according to claim 22,wherein the propeller system is first removed from the head and is thenreplaced by a replacement propeller system.
 24. The method according toclaim 22, wherein the propeller system is lifted using a crane providedon or by the wind turbine, the crane being mounted on the head of thewind turbine.
 25. The method for maintenance of a wind turbine farm,comprising a series of wind turbines, each wind turbine being the windturbine according to claim 1, wherein the series of turbines comprises Nturbines, each wind turbine comprising a propeller system, wherein atleast one further propeller system is provided for exchange with any oneof the propeller systems of the wind turbines, wherein for maintenanceof a propeller system said propeller system is removed from the windturbine and replaced by said further propeller system, wherein thepropeller system removed is configured to be shipped to a maintenancelocation remote from the relevant wind turbine or wind turbine farm.